61 transformer blocks › 60 MoE blocks › Latent attention
Values
×tensorvalue_states
64 value heads of 128 features.
- shape
- [B batch, 64 heads, T positions, 128 value]
Sources
Contextual evidence from Value heads
MLA owns a query down-projection, query RMSNorm and up-projection, a joint key–value down-projection that also emits the shared rotary key, a latent RMSNorm, a key–value up-projection and an output projection.
mla-init · moonshotai/Kimi-K2-Instruct / modeling_deepseek.py
Pinned revision fd1984e2b7a3 ↗ · lines 662–688
Read code excerpt
self.q_a_proj = nn.Linear(
self.hidden_size, config.q_lora_rank, bias=config.attention_bias
)
self.q_a_layernorm = DeepseekV3RMSNorm(config.q_lora_rank)
self.q_b_proj = nn.Linear(
config.q_lora_rank, self.num_heads * self.q_head_dim, bias=False
)
self.kv_a_proj_with_mqa = nn.Linear(
self.hidden_size,
config.kv_lora_rank + config.qk_rope_head_dim,
bias=config.attention_bias,
)
self.kv_a_layernorm = DeepseekV3RMSNorm(config.kv_lora_rank)
self.kv_b_proj = nn.Linear(
config.kv_lora_rank,
self.num_heads
* (self.q_head_dim - self.qk_rope_head_dim + self.v_head_dim),
bias=False,
)
self.o_proj = nn.Linear(
self.num_heads * self.v_head_dim,
self.hidden_size,
bias=config.attention_bias,
)
self._init_rope()Contextual evidence from Value heads
The rotary parts are rotated; each head’s query and key join their non-rotated and rotated parts, the key’s rotated part being the shared rotary key; scores are scaled, masked by the causal mask, normalized and used to mix values.
mla-prefill · moonshotai/Kimi-K2-Instruct / modeling_deepseek.py
Pinned revision fd1984e2b7a3 ↗ · lines 799–840
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cos, sin = self.rotary_emb(value_states, seq_len=kv_seq_len)
q_pe, k_pe = apply_rotary_pos_emb(q_pe, k_pe, cos, sin, position_ids)
query_states = k_pe.new_empty(bsz, self.num_heads, q_len, self.q_head_dim)
query_states[:, :, :, : self.qk_nope_head_dim] = q_nope
query_states[:, :, :, self.qk_nope_head_dim :] = q_pe
key_states = k_pe.new_empty(bsz, self.num_heads, q_len, self.q_head_dim)
key_states[:, :, :, : self.qk_nope_head_dim] = k_nope
key_states[:, :, :, self.qk_nope_head_dim :] = k_pe
if past_key_value is not None:
cache_kwargs = {"sin": sin, "cos": cos} # Specific to RoPE models
key_states, value_states = past_key_value.update(
key_states, value_states, self.layer_idx, cache_kwargs
)
attn_weights = (
torch.matmul(query_states, key_states.transpose(2, 3)) * self.softmax_scale
)
if attn_weights.size() != (bsz, self.num_heads, q_len, kv_seq_len):
raise ValueError(
f"Attention weights should be of size {(bsz, self.num_heads, q_len, kv_seq_len)}, but is"
f" {attn_weights.size()}"
)
assert attention_mask is not None
if attention_mask is not None:
if attention_mask.size() != (bsz, 1, q_len, kv_seq_len):
raise ValueError(
f"Attention mask should be of size {(bsz, 1, q_len, kv_seq_len)}, but is {attention_mask.size()}"
)
attn_weights = attn_weights + attention_mask
# upcast attention to fp32
attn_weights = nn.functional.softmax(
attn_weights, dim=-1, dtype=torch.float32
).to(query_states.dtype)
attn_weights = nn.functional.dropout(
attn_weights, p=self.attention_dropout, training=self.training
)
attn_output = torch.matmul(attn_weights, value_states)Contextual evidence from KV cache
With a cache, the cached length is added to this call’s, the rebuilt and rotated keys and the values are handed to the cache object, which returns every cached key and value so far, and the scores cover all of them.
kv-cache · moonshotai/Kimi-K2-Instruct / modeling_deepseek.py
Pinned revision fd1984e2b7a3 ↗ · lines 790–824
Read code excerpt
kv_seq_len = value_states.shape[-2]
if past_key_value is not None:
if self.layer_idx is None:
raise ValueError(
f"The cache structure has changed since version v4.36. If you are using {self.__class__.__name__} "
"for auto-regressive decoding with k/v caching, please make sure to initialize the attention class "
"with a layer index."
)
kv_seq_len += past_key_value.get_usable_length(kv_seq_len, self.layer_idx)
cos, sin = self.rotary_emb(value_states, seq_len=kv_seq_len)… lines 800–809 omitted …
if past_key_value is not None:
cache_kwargs = {"sin": sin, "cos": cos} # Specific to RoPE models
key_states, value_states = past_key_value.update(
key_states, value_states, self.layer_idx, cache_kwargs
)
attn_weights = (
torch.matmul(query_states, key_states.transpose(2, 3)) * self.softmax_scale
)
if attn_weights.size() != (bsz, self.num_heads, q_len, kv_seq_len):
raise ValueError(
f"Attention weights should be of size {(bsz, self.num_heads, q_len, kv_seq_len)}, but is"
f" {attn_weights.size()}"
)Contextual evidence from KV cache
The joint down-projection yields the key–value latent and one rotary key shared by all heads; the latent is normalized and up-projected into per-head content keys and values.
mla-kv · moonshotai/Kimi-K2-Instruct / modeling_deepseek.py
Pinned revision fd1984e2b7a3 ↗ · lines 776–789
Read code excerpt
compressed_kv = self.kv_a_proj_with_mqa(hidden_states)
compressed_kv, k_pe = torch.split(
compressed_kv, [self.kv_lora_rank, self.qk_rope_head_dim], dim=-1
)
k_pe = k_pe.view(bsz, q_len, 1, self.qk_rope_head_dim).transpose(1, 2)
kv = (
self.kv_b_proj(self.kv_a_layernorm(compressed_kv))
.view(bsz, q_len, self.num_heads, self.qk_nope_head_dim + self.v_head_dim)
.transpose(1, 2)
)
k_nope, value_states = torch.split(
kv, [self.qk_nope_head_dim, self.v_head_dim], dim=-1
)Contextual evidence from KV cache
The released configuration: width, layers, dense layers, heads, routed and shared experts, routing (sigmoid scores, one expert group, top-8 of 384, route scale 2.827), MLA ranks and head widths, vocabulary, YaRN RoPE.
config · moonshotai/Kimi-K2-Instruct / config.json
Pinned revision fd1984e2b7a3 ↗ · lines 1–68
Read code excerpt
{
"architectures": [
"DeepseekV3ForCausalLM"
],
"attention_bias": false,
"attention_dropout": 0.0,
"auto_map": {
"AutoConfig": "configuration_deepseek.DeepseekV3Config",
"AutoModel": "modeling_deepseek.DeepseekV3Model",
"AutoModelForCausalLM": "modeling_deepseek.DeepseekV3ForCausalLM"
},
"aux_loss_alpha": 0.001,
"bos_token_id": 163584,
"eos_token_id": 163585,
"first_k_dense_replace": 1,
"hidden_act": "silu",
"hidden_size": 7168,
"initializer_range": 0.02,
"intermediate_size": 18432,
"kv_lora_rank": 512,
"max_position_embeddings": 131072,
"model_type": "kimi_k2",
"moe_intermediate_size": 2048,
"moe_layer_freq": 1,
"n_group": 1,
"n_routed_experts": 384,
"n_shared_experts": 1,
"norm_topk_prob": true,
"num_attention_heads": 64,
"num_experts_per_tok": 8,
"num_hidden_layers": 61,
"num_key_value_heads": 64,
"num_nextn_predict_layers": 0,
"pretraining_tp": 1,
"q_lora_rank": 1536,
"qk_nope_head_dim": 128,
"qk_rope_head_dim": 64,
"quantization_config": {
"activation_scheme": "dynamic",
"fmt": "e4m3",
"quant_method": "fp8",
"weight_block_size": [
128,
128
]
},
"rms_norm_eps": 1e-06,
"rope_theta": 50000.0,
"routed_scaling_factor": 2.827,
"rope_scaling": {
"beta_fast": 1.0,
"beta_slow": 1.0,
"factor": 32.0,
"mscale": 1.0,
"mscale_all_dim": 1.0,
"original_max_position_embeddings": 4096,
"type": "yarn"
},
"scoring_func": "sigmoid",
"seq_aux": true,
"tie_word_embeddings": false,
"topk_group": 1,
"topk_method": "noaux_tc",
"torch_dtype": "bfloat16",
"transformers_version": "4.48.3",
"use_cache": true,
"v_head_dim": 128,
"vocab_size": 163840